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Commit 05dbcb43 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin
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virtio: virtio 1.0 cs04 spec compliance for reset 



The spec says: after writing 0 to device_status, the driver MUST wait
for a read of device_status to return 0 before reinitializing the
device.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
parent e8aabc64

drivers/virtio/virtio_pci_modern.c

+8 −3
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
 *

 */



#include <linux/delay.h>

#define VIRTIO_PCI_NO_LEGACY

#include "virtio_pci_common.h"
@@ -271,9 +272,13 @@ static void vp_reset(struct virtio_device *vdev) 
	struct virtio_pci_device *vp_dev = to_vp_device(vdev);

	/* 0 status means a reset. */

	vp_iowrite8(0, &vp_dev->common->device_status);

	/* Flush out the status write, and flush in device writes,

	 * including MSI-X interrupts, if any. */

	vp_ioread8(&vp_dev->common->device_status);

	/* After writing 0 to device_status, the driver MUST wait for a read of

	 * device_status to return 0 before reinitializing the device.

	 * This will flush out the status write, and flush in device writes,

	 * including MSI-X interrupts, if any.

	 */

	while (vp_ioread8(&vp_dev->common->device_status))

		msleep(1);

	/* Flush pending VQ/configuration callbacks. */

	vp_synchronize_vectors(vdev);

}